It hatched in the episode Hatching a Plan. It was shown to be a very playful and energetic Pokémon, refusing to be returned to its Poké Ball, only to be snatched by Team Rocket. Pikachu rescued Phanpy, but the electricity scared the baby Pokémon away. It ran into the clutches of Team Rocket again, who used Meowth to deceive Phanpy and hatch a plot to capture Pikachu. After this plan succeeds, Team Rocket double crossed Phanpy and stuck it in a cage, only for Pikachu to hatch an escape plan and Ash to come to the rescue, selflessly diving into the river to rescue Phanpy. It was then used Rollout to knock back Team Rocket's Pokémon for Pikachu to send them blasting off. It was unable to replicate this success in the next episode, where Team Rocket used Delibird's Blizzard to knock out Phanpy in a single blow.

In Pop Goes The Sneasel, Phanpy joined Harrison's Houndoom in taking down a rogue Machop with Rollout while recovering the stolen Sacred Fire for the Johto League opening ceremony. It also helped him get through the screening phases of the Silver Conference.

Phanpy played a role in Ash's battle against Macy in the Silver Conference in the episode Love, Pokémon Style. It was used in counter to her Electabuzz, and this succeeded as Electabuzz's Thunderbolt had no effect. However, Macy pulled Electabuzz and Phanpy ended up battling against her Slugma. Phanpy managed to dodge Slugma's Body Slam and stun Slugma with Earthquake, before knocking it out with Take Down. However, it was defeated by her Quilava's powerful Flame Wheel, which overpowered Phanpy's Rollout and left Ash's Squirtle and Totodile to face Electabuzz.

Ash left Phanpy at Professor Oak's lab before traveling to Hoenn. In The Right Place and the Right Mime, it happily greeted Ash's Pikachu and the two spent most of the episode together. As Ash made to leave at the end of the episode to take on the Battle Frontier challenge, Pikachu rode up on Phanpy's back. Ash offered to let Phanpy come with them, which Phanpy delightedly agreed to. It had shown signs that it had grown up beyond the young Pokémon seen in Johto.

In, Queen of the Serpentine!, Ash used Donphan as his first Pokémon in his Battle Pike challenge against Pike Queen Lucy, Donphan went up against her Seviper, since it had the type advantage and would be good on the swamp terrain. Donphan used Take Down while Seviper used Poison Tail and they were shown to be evenly matched. Seviper used Bite but was blocked with Defense Curl and hit it with its Rollout. However a second Rollout was dodged and Donphan was hit with Poison Tail, but Ash used Donphan's rolling power to jump and use a powerful Take Down but Seviper countered with Flamethrower hitting Donphan. Donphan used Hyper Beam but Seviper was quicker and used Poison Tail, though Donphan withstood the attack and used Hyper Beam but Seviper used Poison Tail on the water to create a splash blocking the attack and creating smoke, making both sides unable to see, despite this Seviper was able to get off a Flamethrower, but Donphan dodged and used Rollout but Lucy got Seviper to hit Donphan with Flamethrower. Ash had Donphan roll into the flames, setting it on fire, and then jump from the rock to hit Seviper, knocking it out. Donphan then went up against Milotic, which had the type advantage, Donphan used Rollout, but Milotic countered with Hydro Pump, stopping Take Down and knocking out Donphan.

In Grating Spaces!, Ash used Donphan in a Double Battle with Brock and his Steelix against Jessie, James and their newly obtained Charizard and Aggron. The two Pokémon worked well together, with Donphan rescuing Steelix from Charizard's Flamethrower by attacking Charizard recklessly. However, Aggron fought back with Mega Punch and Hyper Beam, knocking Donphan back. Donphan recovered and kept attacking Charizard, but Aggron's Water Pulse took it down. Steelix propelled Donphan over the subsequent wave of water and allowed it to hit Aggron. At this point, the battle ended when Forrest confronted Team Rocket's objectives.

Donphan appeared in An Old Family Blend!, alongside Ash's other Pokémon. It was shown training with Ash.

In Working on a Right Move!, Ash used Donphan as his second Pokémon in his battle against Conway in the third round of the Lily of the Valley Conference. Shuckle used Sludge Bomb but Donphan used Rollout, making Sludge Bomb useless, Shuckle then used Gyro Ball, which was powered up by Power Trick, halving the attack power of Rollout as well as causing Donphan to crash on a hill. It was then returned. It later went up against Dusknoir, due to the effect of Trick Room, since it was normally faster than Dusknoir, Dusknoir always attacked first. Donphan jumped up to use Rollout but Dusknoir used Shadow Punch, knocking Donphan into the ground, Ash tried to recall it, but Dusknoir used Mean Look to prevent it from being returned, it was then knocked out by another Shadow Punch.

Donphan was reunited with Ash in The Dream Continues!, where it and the rest of Ash's Pokémon posed in a group photo with him.

Personality and characteristics

As a Phanpy, it had many traits of a child being extremely playful, friendly and energetic. It at first thought everyone around it was playing, even in a serious situation. It was also easily frightened from not knowing how to handle damage. However, it matured after evolving into Donphan, much like his Aipom did later. In some episodes, as shown in Odd Pokémon Out!, it was shown to have kept its friendly personality upon evolution. As a Phanpy, Donphan was initially one of Ash's weaker Pokémon, but it would gradually become stronger battle after battle. Donphan is generally loyal to Ash, and always tries its best for him in battles.

In the TCG

Ash's PhanpyCards listed with a blue background are only legal to use in the current Expanded format.Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.